This blog looks at some of the facts about Vitamin D, and intriguingly, how a lack of the ‘sunshine vitamin’ is being implicated in a host of diseases never previously associated with it. Vitamin D allows us to absorb calcium, iron, magnesium and zinc, and is crucial for tooth and bone development. Around 80% of our vitamin D is synthesised by our body when our skin is exposed to sunlight, so the further we live from the equator, the more we rely on our diet for the remaining 20% we need.

In England, all pregnant and breastfeeding mothers are advised to take daily 10mg vitamin D supplements to ensure adequate foetal stores for early infancy, addressing the fact we live in a climate where sunlight levels are low. (Observational studies have shown that a mother’s Vitamin D level during pregnancy can even influence the growth of her infant. In addition, Vitamin D drops are advised for children aged 6 months to 5 years. Yet, recent research commissioned by health insurer, BUPA, points to only 1 in 25 parents doing so.

And although vitamin D was discovered in the early 1900s, more and more is being discovered about its role in diseases affecting both young and old, such as osteoporosis, multiple sclerosis and even diabetes.

RICKETS: A HORROR RETURNS

Over the past few years, doctors and public health workers have been saddened to see Vitamin D deficiency return in the form of rickets. Rickets is characterised by misformed bones, dental issues, and muscle weakness. It occurs when the process of mineralisation – bone building – goes wrong. It may be due to over-use of sun block, not getting into the sun enough, or for cultural reasons involving covering up of the skin. Despite having high sunshine levels, the Middle East has the highest rate of rickets in the world, due to such cultural practices, and due to a lack of vitamin D supplementation for breast-feeding women.

FORTIFIED BRITAIN?

In England, the post war decades saw food being fortified with Vitamin D, which was added to margarine and some cereals. It was thought rickets had been entirely eradicated, but in the 1970s, it reappeared when different ethnic groups migrated to the UK. Children of Asian, Afro-Caribbean and Middle Eastern parents with darker skin required more sunlight exposure to get enough Vitamin D, so those children were more likely to develop rickets.

In 2010, the British Medical Journal reported that doctors in Newcastle (where sunlight levels are lower than in the South of England) were seeing 20 cases per year. It would seem that good patient education for this entirely preventable disease is of great importance once more. But is supplementation or food fortification needed? With our wealth of ethnicity, and so many variations in our diet, some say fortification would fail to provide a ‘catch all’ approach. Yet, as a nation, we don’t seem to have taken this deficiency to heart. In 1999, Britain was the only EU country that didn’t have an RDA (recommended daily allowance) for it.

CAN’T BITE, CAN’T FIGHT

We’ve come a long way in the past 100 years to understanding nutrition. When soldiers were recruited to fight in the Boer War (1899 – 1902) of the 8,000 men from Manchester who joined, 6,800 displayed signs of incapacity caused by childhood illnesses, including rickets, which presented significant drawbacks from a military strength point of view. Such was the poor state of the recruits’ teeth, thanks to a lack of Vitamin D (and poor oral hygiene), that the expression ‘Can’t bite, can’t fight’ was coined. Intriguingly, medics noted that Scotsmen fared better than most, which they put down to habitual doses of cod liver oil – even before Vitamin D had been discovered! The Scots’ belief was dismissed at the time as an old wives’ tale, and sadly it took decades before the truth emerged: oily fish does contain high levels of the vitamin.

NEW DISCOVERIES: LINKS TO MS, DIABETES AND MORE

Today, with genetic profiling and other lab techniques, we are discovering even more benefits of the sunshine Vitamin. Deficiency has been linked to the debilitating disease, multiple sclerosis, MS, for a long time. It is a disease almost unheard of near the equator, with incidence rising incrementally towards the poles, where sunshine levels are lowest. Although MS affects women more than men, as far back as the 1960s, it was noted by the military (which keeps helpful, large data sets of medical records) that a healthy, outdoor lifestyle amongst US veterans provided the ideal protection from MS.

The powerful effect of the seasons – ergo, Vitamin D – can also be seen in the number of those suffering immune disorders. Even within Britain, there is a notable north-south divide in the incidence of such disorders, with more cases the further north you look. In the 1980s, Vitamin D was found to normalise blood glucose levels by increasing insulin release. Then, in the 90s, the link established between the seasons and glycaemia (blood glucose). Now, it’s been proven that adequate Vitamin D reduces the risk of type 1 diabetes because it suppresses acquired immunity. As for type 2, it can help decrease insulin resistance – the first feature of this increasingly common, and enormously costly, disease.

NEVERMIND THE STARSIGN

In the light of the above, you may wish to know that April is the least ‘lucky’ month in which to be born: should your birthday fall around that month, your mother will have spent the majority of her pregnancy without much exposure to sunlight – unless she’s been holidaying abroad, for instance.

Lately, there’s been an increased focus on the link between Vitamin D and athletic performance. Dr Graeme L Close, senior lecturer in sports nutrition at Munster Rugby, has been asking; Why do jockeys (known for their leanness) have far lower levels of Vitamin D than their bulkier counterpart athletes, rugby players? He is testing the hypothesis that Vitamin D has a role in muscle mass. Certainly, ballet dancers who are given supplements of the vitamin (rather than a placebo) were found to be able to increase their vertical jump height and lower their injury rate; not a bad pointe (sic).

INDOOR LIVING: A TICKING TIME BOMB?

We know that lifestyle changes over the past 50 years have affected our health for the worse, immeasurably, as seen in obesity and diabetes epidemics. Are we facing a ticking time bomb of Vitamin D deficiency, which is storing up problems for later life in our children and young adults? Perhaps we should get kids outside with their handheld devices, and take full advantage of ‘wireless’.

Further research into Vitamin D’s effects on health is needed. A key issue is controlling such trials effectively, because Vitamin D isn’t like a measurable drug which can be monitored precisely, because we synthesis it from our exposure to sunlight. Yet, the message is ‘don’t’ give up’. Afterall, it took 40 years for the medical world to accept that sunshine would prevent rickets. In the meantime, we can take comfort that with the long winter ahead, dark chocolate is high in this precious vitamin. Now that’s a win-win situation….